Problem: I used $9$ sheets of toilet paper each day for $7$ days. The roll had $96$ sheets when it was new. How many sheets of toilet paper have not been used?
Answer: $\text{Used}$ $\text{Unused}$ ${?}$ $7 \times 9$ ${96}$ $63$ I used $9$ sheets of toilet paper each day for $7$ days. We can multiply to find the number of sheets used. I have used $7\times9={63}$ sheets. ${\text{Total}}$ sheets of paper $-$ sheets of paper ${\text{used}}$ $=$ number of sheets left on the ${\text{roll}}$ ${96}-{63}={33}$ ${33}$ sheets have not been used.